In many industries, it is quite common to use tubular mechanisms or assemblies to carry out reactions or perform other necessary functions. This is especially true in the heating, ventilating and air conditioning industry (commonly called HVAC). Such procedures are most efficiently run when the tubes are clear or clean. Sometimes, in fact usually and almost always, deposits form within the tubes during the course of the reactions and cause the tubes to fill with residue.
Shaft driven tube cleaners are known to be suitable for cleaning the tubes, which are customarily used in the HVAC industry. More particularly, a shaft driven tube cleaner may be used to carry out maintenance functions on a boiler or a chiller, or a related sheet and tube heat exchanger. Clean tube surfaces, especially interior surfaces are required for maximum designed heat transfer, thus insuring efficient operation of the heat transfer device, in the tubes are mounted.
Tube cleaning shafts suffer damage from over torquing, especially when the cleaning tool mounted on the end of the flexible shaft gets stuck in deposits within the tube. There is no good way to know, that the tube cleaning shaft is being over torqued, until after the damage is done, even to a point beyond repair. It is desirable to prevent this damage and to provide information and immediate activation by the operator of relief procedures as soon as the over torquing occurs.
It is also desired to provide for the cleaning shaft to be mounted easily to the power unit. If such mounting can be simplified, great advantages can be obtained. Not only is the tool more easily used, cleaning efficiency is greatly improved at reasonable expense. For example, a special power unit is not required.
One example of a prior art tube cleaning system 110 can be seen by considering FIG. 1 and FIG. 2 together. The cleaning system 110 has a power unit 112 and flexible shaft assembly 114. One prior art coupling unit 116 for use with power unit 112, as shown in FIG. 2, has a drive shaft 120, which receives standard coupling 122 in male/female relationship. Shaft anchor pin 124 passes through both standard coupling aperture 126 and the concentric drive shaft aperture 128, locking drive shaft 120 and standard coupling 122 together.
When a cleaning tool 108 mounted on the flexible shaft assembly 114 locks up during a tube cleaning process for tube 106, stress is put first on standard coupling 122, and then on power unit 112 as well as flexible shaft assembly 114. At least one of those parts may be ruined if power is not terminated immediately.
If over torquing can be avoided, both damage to power source and damage to the flexible shaft can be avoided. Thus, some manner of detecting over torquing before damage is done is extremely useful.